Characteristics of folliculogenesis, steroidogenesis, and oogenesis during ovarian stimulation in the luteal phase of the menstrual cycle

Aim. To investigate the effectiveness of ovarian stimulation in different phases of the menstrual cycle to preserve reproductive material in cancer patients. Materials and methods. Patients requiring gonadotoxic treatment for cancer (n=140) underwent ovarian stimulation according to the standard protocol with the gonadotrophin-releasing hormone (GnRH) antagonist in the follicular phase (n=68) and random-start protocol in the luteal phase without GnRH antagonists (n=72). The comparative analysis included starting and total gonadotropin doses, stimulation duration, and outcomes (mature oocyte and blastocyst counts, fertilization rate). Results. All patients included in the study were comparable in age and serum levels of anti-Mtillerian hormone (AMH). The mean age of women in groups I and II was 33.3 (3.7) and 33.3 (5.47) years, respectively. AMH level was (3.0 (2.1) and 2.7(0.4) ng/ml, respectively. There was no statistically significant difference in the starting, daily, and total gonadotropin doses between the two groups. The findings demonstrated that ovarian stimulation with gonadotropins in the luteal phase is accompanied by a high progesterone level, which does not require a GnRH antagonist administration while inducing follicular growth. This produces comparable results with stimulation in the follicular phase in terms of the number of obtained and mature oocytes and the fertilization rate. Conclusion. The present study’s findings suggest equal effectiveness of stimulation protocols irrespective of menstrual cycle phase, which allows tailoring treatment both for cancer patients and in the routine practice of ART. The protective effect of progesterone against spontaneous LH-surge allows stimulation in the luteal phase without additional administration of a GnRH antagonist.

ovarian stimulation, random-start protocols, oncofertility, progesterone